Do not validate path dependencies when they are not selected for installation

• I am on the latest Poetry version.
• I have searched the issues of this repo and believe that this is not a duplicate.
• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: Ubuntu 18.10
• Poetry version: 0.12.10
• Link of a Gist with the contents of your pyproject.toml file: https://gist.github.com/spither/47f144b1f355990d562b5ba92bf15fe3

Issue

I cannot run poetry install --no-dev away from my development environment because I have dev-only path based dependencies.

> poetry install --no-dev
                                    
[ValueError]             
Directory ../dev-only does not exist  

The error is correct, the directory doesn’t exist, but it’s only listed as a dev-dependency and I’m trying to install --no-dev. I was not expecting any dev-dependency checks to take place.

In my case I’m trying to install the non-dev dependencies for a Django site deployment. The path based dev-dependencies only exist in development, not on the deployment system.

[rphes]

I’ve also run into this issue, my use case being that I want to use a local (and editable) version of a package during development and a commit from a git repository for deployment situations.

[tall-josh]

I know it’s a MASSIVE hack but this was killing my docker build and I didn’t want two pyproject.toml so I just put the [tool.poetry.dev-dependencies] heading at the bottom of my pyproject.toml and used RUN sed -i -n '/tool.poetry.dev-dependencies/q;p' pyproject.toml before poetry install.

I know. I feel dirty, but I regret nothing!